Waveguides with integrated optical elements and methods of making the same

ABSTRACT

An example waveguide can include a polymer layer having substantially optically transparent material with first and second major surfaces configured such that light containing image information can propagate through the polymer layer being guided therein by reflecting from the first and second major surfaces via total internal reflection. The first surface can include first smaller and second larger surface portions monolithically integrated with the polymer layer and with each other. The first smaller surface portion can include at least a part of an in-coupling optical element configured to couple light incident on the in-coupling optical element into the polymer layer for propagation therethrough by reflection from the second major surface and the second larger surface portion of the first major surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. § 371of International Application No. PCT/US2019/025195, filed on Apr. 1,2019, which published in English as WO 2019/195174 A1 on Oct. 10, 2019,and which claims the benefit of priority under 35 U.S.C. § 119(e) ofU.S. Provisional Application No. 62/651,553 filed on Apr. 2, 2018. Theentirety of each application referenced in this paragraph is expresslyincorporated herein by reference.

INCORPORATION BY REFERENCE

This application incorporates by reference the entirety of each of thefollowing patent applications: U.S. application Ser. No. 14/555,585filed on Nov. 27, 2014, published on Jul. 23, 2015 as U.S. PublicationNo. 2015/0205126; U.S. application Ser. No. 14/690,401 filed on Apr. 18,2015, published on Oct. 22, 2015 as U.S. Publication No. 2015/0302652;U.S. application Ser. No. 14/212,961 filed on Mar. 14, 2014, now U.S.Pat. No. 9,417,452 issued on Aug. 16, 2016; and U.S. application Ser.No. 14/331,218 filed on Jul. 14, 2014, published on Oct. 29, 2015 asU.S. Publication No. 2015/0309263.

BACKGROUND Field

The present disclosure relates to display systems and, moreparticularly, to augmented reality display systems.

Description of the Related Art

Modern computing and display technologies have facilitated thedevelopment of systems for so called “virtual reality” or “augmentedreality” experiences, wherein digitally reproduced images or portionsthereof are presented to a user in a manner wherein they seem to be, ormay be perceived as, real. A virtual reality, or “VR”, scenariotypically involves presentation of digital or virtual image informationwithout transparency to other actual real-world visual input; anaugmented reality, or “AR”, scenario typically involves presentation ofdigital or virtual image information as an augmentation to visualizationof the actual world around the user. A mixed reality, or “MR”, scenariois a type of AR scenario and typically involves virtual objects that areintegrated into, and responsive to, the natural world. For example, inan MR scenario, AR image content may be blocked by or otherwise beperceived as interacting with objects in the real world.

Referring to FIG. 1, an augmented reality scene 10 is depicted wherein auser of an AR technology sees a real-world park-like setting 20featuring people, trees, buildings in the background, and a concreteplatform 30. In addition to these items, the user of the AR technologyalso perceives that he “sees” “virtual content” such as a robot statue40 standing upon the real-world platform 30, and a cartoon-like avatarcharacter 50 flying by which seems to be a personification of a bumblebee, even though these elements 40, 50 do not exist in the real world.Because the human visual perception system is complex, it is challengingto produce an AR technology that facilitates a comfortable,natural-feeling, rich presentation of virtual image elements amongstother virtual or real-world imagery elements.

Systems and methods disclosed herein address various challenges relatedto AR and VR technology.

SUMMARY

This disclosure provides various examples of waveguides, systems, andmethods. Each example has several innovative aspects, no single one ofwhich is solely responsible for the desirable attributes disclosedherein.

1. A waveguide comprising:

-   -   a polymer layer comprising substantially optically transparent        material having first and second major surfaces configured such        that light containing image information can propagate through        said polymer layer being guided therein by reflecting from said        first and second major surfaces via total internal reflection,    -   wherein said first surface includes first smaller and second        larger surface portions monolithically integrated with said        polymer layer and with each other, said first smaller surface        portion comprising at least a part of an in-coupling optical        element configured to couple light incident on said in-coupling        optical element into said polymer layer for propagation        therethrough by reflection from said second major surface and        said second larger surface portion of said first major surface.

2. The waveguide of Example 1, wherein said in-coupling optical elementcomprises a turning mirror configured to deflect light containing imageinformation in the waveguide.

3. The waveguide of Example 2, wherein said turning mirror comprisessaid first smaller surface portion of said first major surface tiltedwith respect to said second larger surface portion of said first majorsurface and said second major surface.

4. The waveguide of Example 2 or 3, wherein said turning mirror hasoptical power.

5. The waveguide of Example 4, wherein said powered turning mirrorcomprises said first smaller surface portion of said first major surfacecurved with respect to said second larger surface portion of said firstmajor surface and said second major surface.

6. The waveguide of any of Examples 2 to 5, wherein said turning mirrorfurther comprises metallization disposed on said first smaller surfaceportion of said first major surface.

7. The waveguide of Example 1, wherein said in-coupling optical elementcomprises a lens.

8. The waveguide of Example 7, wherein said lens comprises said firstsmaller surface portion of said first major surface curved with respectto said second larger surface portion of said first major surface andsaid second major surface.

9. The waveguide of Example 1, wherein said in-coupling optical elementcomprises a grating.

10. The waveguide of Example 9, wherein said grating comprises saidfirst smaller surface portion of said first major surface having anundulating surface relief.

11. The waveguide of any of Examples 1-10, wherein said polymer layerincluding said at least a part of said in-coupling optical elementcomprises a molded optic.

12. The waveguide of any of Examples 1 to 11, wherein the plurality ofsurfaces has a surface roughness between about 0.1 nm to about 2.0 nm.

13. A waveguide comprising:

-   -   a molded optic comprising a molded layer of substantially        optically transparent material, said molded layer having first        and second major surfaces configured such that light containing        image information can propagate through said molded layer being        guided therein by reflecting from said first and second major        surfaces via total internal reflection,    -   wherein said first surface includes first smaller and second        lamer surface portions monolithically integrated with said        molded layer and with each other, said first smaller surface        portion comprising at least a part of a molded in-coupling        optical element configured to couple light incident on said        molded in-coupling optical element into said molded layer for        propagation therethrough by reflection from said second major        surface and said second larger surface portion of said first        major surface.

14. A waveguide comprising:

-   -   a polymer layer configured to propagate light containing image        information therethrough;    -   a plurality of surfaces sufficient to guide the image        information in the polymer layer by total internal reflection;        and    -   a tilted surface portion forming at least a part of an        in-coupling optical element that is configured to deflect light        containing image information in the waveguide.

15. The waveguide of Example 14, wherein said tilted surface portionforms an indentation in said polymer layer.

16. The waveguide of Example 15, wherein said indentation in saidpolymer layer is at least ½ the thickness of said polymer layer.

17. The waveguide of Example 15, wherein said indentation in saidpolymer layer is at least ¾ the thickness of said polymer layer.

18. The waveguide of any of Examples 14 to 17, wherein said tiltedsurface portion is tilted between about 40°-50° with respect to saidplurality of surfaces.

19. The waveguide of any of Examples 14 to 18, wherein said in-couplingoptical element comprises a turning mirror comprising metallization.

20. The waveguide of any of Examples 14 to 19, wherein the tiltedsurface portion comprises curvature to provide optical power.

21. The waveguide of any of Examples 14 to 20, wherein said polymerlayer, said plurality of surfaces, and said tilted surface portioncomprise a molded optic.

22. The waveguide of any of Examples 14 to 21, wherein the plurality ofsurfaces has a surface roughness between about 0.1 nm to about 2.0 nm.

23. A waveguide comprising:

-   -   an optically transparent layer comprising optically transparent        material and a plurality of surfaces sufficient to guide light        containing image information in the waveguide by total internal        reflection; and    -   a tilted surface portion forming at least a part of an        in-coupling optical element that is configured to deflect light        containing image information in the waveguide such that said        light is guided in said optically transparent layer, wherein the        tilted surface portion comprises curvature to provide optical        power.

24. The waveguide of Example 23, wherein said optical power comprisespositive optical power.

25. The waveguide of Example 23 or 24, wherein said tilted surfaceportion has a concave curvature from the perspective of most locationswithin in the optically transparent layer.

26. The waveguide of any of Examples 23 to 25, wherein the in-couplingoptical element is a mirror, a facet, a prism, or a combination thereof.

27. The waveguide of any of Examples 23 to 26, wherein the in-couplingoptical element further comprises a metal layer on said tilted surfaceportion.

28. The waveguide of any of Examples 23 to 27, wherein each of theplurality of surfaces has a surface roughness between about 0.1 nm toabout 2.0 nm.

29. The waveguide of any of Examples 23 to 28, wherein the opticallytransparent material comprises a polymer.

30. The waveguide of any of Examples 23 to 29, wherein the opticallytransparent layer, plurality of surfaces, and tilted surface portioncomprise a molded optic.

31. A waveguide comprising:

-   -   an optically transparent layer comprising optically transparent        material and first and second surfaces sufficient to guide light        containing image information in the waveguide by total internal        reflection; and    -   a surface portion on said first surface forming at least a part        of a lens, said surface portion being curved.

32. The waveguide of Example 31, wherein the lens comprises a convexlens.

33. The waveguide of Example 31 or 32, wherein said lens comprises apositive powered lens.

34. The waveguide of any of Examples 31 to 33, wherein the lens isaligned with an in-coupling optical element configured to turn lightreceived by the in-coupling optical element after passing through thelens into the layer of optically transparent material to be guidedtherein.

35. The waveguide of Example 34, wherein the in-coupling optical elementis disposed on the second surface of the layer of optically transparentmaterial.

36. The waveguide of any of Examples 31 to 35, wherein each of theplurality of surfaces has a surface roughness between about 0.1 nm toabout 2.0 nm.

37. The waveguide of any of Examples 31 to 36, wherein the opticallytransparent material comprises a polymer.

38. The waveguide of any of Examples 31 to 37, wherein the opticallytransparent layer, the first and second surfaces, and the lens comprisea molded optic.

39. A waveguide comprising:

-   -   an optically transparent layer comprising optically transparent        material and first and second surfaces sufficient to guide light        containing image information in the waveguide by total internal        reflection; and    -   a surface portion on said first surface forming at least a part        of an anti-reflective structure, said anti-reflective structure        comprising a surface relief pattern on said first surface.

40. The waveguide of Example 39, wherein said anti-reflective structurecomprises an undulating pattern.

41. The waveguide of any of Examples 39 or 40, wherein saidanti-reflective structure comprises a periodic pattern.

42. The waveguide of Example 41, wherein the periodic pattern has aperiod from about 50 nm to about 200 nm.

43. The waveguide of Examples 41 or 42, wherein the periodic pattern hasa height from about 5 nm to about 200 nm.

44. The waveguide of any of Examples 39 to 43, further comprisingmaterial disposed on said surface relief pattern.

45. The waveguide of any of Examples 39 to 44, wherein theanti-reflective structure is optically aligned with an optical elementassociated with another waveguide.

46. The waveguide of Example 45, wherein said optical element is anoptical in-coupling element configured to couple light into said anotherwaveguide.

47. The waveguide of any of Examples 39 to 46, wherein each of the firstand second surfaces has a surface roughness between about 0.1 nm toabout 2.0 nm.

48. The waveguide of any of Examples 39 to 47, wherein the opticallytransparent material comprises a polymer.

49. The waveguide of any of Examples 39 to 48, wherein the opticallytransparent layer, said first and second surfaces, and said surfacerelief pattern comprise a molded optic.

50. An optical system comprising:

-   -   one or more waveguides comprising the waveguide of any of        Examples 1 to 49.

51. The optical system of Example 50, wherein said one or morewaveguides comprising at least two waveguides of any of Examples 1 to49.

52. The optical system of Examples 50 or 51, wherein the optical systemis a head mounted display system configured to project light to an eyeof a user to display augmented reality image content in a vision fieldof said user.

53. The optical system of Example 52, further comprising

-   -   a frame configured to be supported on a head of the user;    -   an image projector configured to project an image; and    -   an eyepiece disposed on the frame, said eyepiece configured to        direct light into said user's eye to display augmented reality        image content to the user's vision field, at least a portion of        said eyepiece being transparent and disposed at a location in        front of the user's eye when the user wears said head-mounted        display system such that said transparent portion transmits        light from the environment in front of the user to the user's        eye to provide a view of the environment in front of the user,        said eyepiece comprising said one or more waveguides.

54. The optical system of Example 53, wherein the image projectorcomprises a scanning fiber display.

55. A method of making a waveguide, the method comprising:

-   -   providing first and second molds, the first mold and the second        mold facing one another, wherein at least the first mold        comprises an imprint of at least a part of at least one        in-coupling optical element;    -   providing a polymer material between the first and second molds;    -   contacting the polymer material with the first and second molds        such that the first mold transfers a corresponding imprint of        the at least a part of the at least one in-coupling optical        element into the polymer material;    -   exposing the polymer material to a hardening process; and    -   removing the polymer material from the first and second molds.

56. The method of Example 55, wherein exposing the polymer material to ahardening process comprises exposing the polymer material to ultravioletlight.

57. The method of Example 55 or 56, wherein the waveguide comprises aplurality of surfaces sufficient to guide light containing imageinformation in the waveguide by total internal reflection.

58. The method of Example 57, wherein the plurality of surfaces has asurface roughness between about 0.1 nm to about 2.0 nm.

59. The method of any of Examples 55 to 58, wherein the at least onein-coupling optical element comprises a tilted surface.

60. The method of Example 59, wherein the tilted surface has curvature.

61. The method of any of Examples 55 to 60, wherein the at least onein-coupling optical element comprises a lens.

62. The method of any of Examples 55 to 61, wherein the at least onein-coupling optical element comprises a grating.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a user's view of augmented reality (AR) through an ARdevice.

FIG. 2 illustrates a conventional display system for simulatingthree-dimensional imagery for a user.

FIGS. 3A-3C illustrate relationships between radius of curvature andfocal radius.

FIG. 4A illustrates a representation of the accommodation-vergenceresponse of the human visual system.

FIG. 4B illustrates examples of different accommodative states andvergence states of a pair of eyes of the user.

FIG. 4C illustrates an example of a representation of a top-down view ofa user viewing content via a display system.

FIG. 4D illustrates another example of a representation of a top-downview of a user viewing content via a display system.

FIG. 5 illustrates aspects of an approach for simulatingthree-dimensional imagery by modifying wavefront divergence.

FIG. 6 illustrates an example of a waveguide stack for outputting imageinformation to a user.

FIG. 7 illustrates an example of exit beams outputted by a waveguide.

FIG. 8 illustrates an example of a stacked waveguide assembly in whicheach depth plane includes images formed using multiple differentcomponent colors.

FIG. 9A illustrates a cross-sectional side view of an example of a setof stacked waveguides that each includes an in-coupling optical element.

FIG. 9B illustrates a perspective view of an example of the plurality ofstacked waveguides of FIG. 9A.

FIG. 9C illustrates a top-down plan view of an example of the pluralityof stacked waveguides of FIGS. 9A and 9B.

FIG. 9D illustrates an example of wearable display system.

FIGS. 10, 11, 12, 13, 14, 15, and 16 illustrate example waveguides withan integrated in-coupling optical element.

FIG. 16A shows a magnified image of an example anti-reflective structureadjacent to an example in-coupling optical element. FIG. 16B shows amagnified image of the example anti-reflective structure.

FIGS. 17A, 17B, 17C, and 17D illustrate an example method of forming awaveguide with an integrated optical element.

DETAILED DESCRIPTION

Waveguides may be utilized to direct light, such as in display devicesincluding head-mounted augmented reality display systems. For example,the waveguides may be incorporated into an eyepiece of eyewear and theviewer may see the ambient environment through the waveguides. Inaddition, the waveguides may project images by receiving lightcontaining image information (e.g., by a projector system) and directingthat light into the eyes of a viewer. The received light may bein-coupled into the waveguides using in-coupling optical elements. Thein-coupled light may subsequently be distributed within the waveguidesusing light distributing elements and out-coupled out of the waveguidesusing out-coupling optical elements.

Low coupling efficiency of the light between the projector system andthe waveguides can lower the total efficiency of the waveguide assemblyand can degrade the overall image quality provided to the viewer.Coupling between optical components can also add constraints on themanufacturing of the display device and/or system (for example,constraints on how to integrate, assemble, align, and package with othercomponents). Accordingly, the in-coupling optical element can affect thedesign.

In-coupling optical elements can include conventional gratings which canhave relatively low in-coupling efficiency of incoming light from aprojector. Conventional gratings can also reflect light back into theprojector, which can be reflected off the projector back into thegrating. The stray light path can produce a ghost image artifact thatcan be distracting. Conventional gratings can also have inherentlydifferent diffraction efficiencies with respect to input angles. Invarious waveguide displays, this can make producing an image withuniform brightness difficult. Nevertheless, sometimes in-couplinggratings may be desired. Prisms and lenses may intrinsically also beadvantageous optically, but can be challenging to fabricate andintegrate.

Certain implementations described herein can include waveguides with anintegrated in-coupling optical element. For example, various waveguidescan include a surface that forms at least a part of the in-couplingoptical element. Compared with waveguides without such an in-couplingoptical element integrated with the waveguide, various implementationscan advantageously provide higher coupling efficiency, better imagequality (e.g., lower ghosting, higher uniformity, etc.), and a simplermanufacturing process. For example, in various implementations, anintegrated optical element can allow direct contact with the waveguide,leading to increased in-coupling and simpler integration. Certainimplementations can advantageously integrate prisms, lenses, and/oranti-reflective structures. Various implementations can reduce ghostimage artifacts, achieve more uniform brightness, and reduce the totalfootprint of the device. Some implementations of waveguides can alsointegrate one or more other optical elements such as light distributingelements and/or out-coupling optical elements.

Reference will now be made to the drawings, in which like referencenumerals refer to like parts throughout. Unless indicated otherwise, thedrawings are schematic not necessarily drawn to scale.

Example Display Systems

FIG. 2 illustrates a conventional display system for simulatingthree-dimensional imagery for a user. It will be appreciated that auser's eyes are spaced apart and that, when looking at a real object inspace, each eye will have a slightly different view of the object andmay form an image of the object at different locations on the retina ofeach eye. This may be referred to as binocular disparity and may beutilized by the human visual system to provide a perception of depth.Conventional display systems simulate binocular disparity by presentingtwo distinct images 190, 200 with slightly different views of the samevirtual object—one for each eye 210, 220—corresponding to the views ofthe virtual object that would be seen by each eye were the virtualobject a real object at a desired depth. These images provide binocularcues that the user's visual system may interpret to derive a perceptionof depth.

With continued reference to FIG. 2, the images 190, 200 are spaced fromthe eyes 210, 220 by a distance 230 on a z-axis. The z-axis is parallelto the optical axis of the viewer with their eyes fixated on an objectat optical infinity directly ahead of the viewer. The images 190, 200are flat and at a fixed distance from the eyes 210, 220. Based on theslightly different views of a virtual object in the images presented tothe eyes 210, 220, respectively, the eyes may naturally rotate such thatan image of the object falls on corresponding points on the retinas ofeach of the eyes, to maintain single binocular vision. This rotation maycause the lines of sight of each of the eyes 210, 220 to converge onto apoint in space at which the virtual object is perceived to be present.As a result, providing three-dimensional imagery conventionally involvesproviding binocular cues that may manipulate the vergence of the user'seyes 210, 220, and that the human visual system interprets to provide aperception of depth.

Generating a realistic and comfortable perception of depth ischallenging, however. It will be appreciated that light from objects atdifferent distances from the eyes have wavefronts with different amountsof divergence. FIGS. 3A-3C illustrate relationships between distance andthe divergence of light rays. The distance between the object and theeye 210 is represented by, in order of decreasing distance, R1, R2, andR3. As shown in FIGS. 3A-3C, the light rays become more divergent asdistance to the object decreases. Conversely, as distance increases, thelight rays become more collimated. Stated another way, it may be saidthat the light field produced by a point (the object or a part of theobject) has a spherical wavefront curvature, which is a function of howfar away the point is from the eye of the user. The curvature increaseswith decreasing distance between the object and the eye 210. While onlya single eye 210 is illustrated for clarity of illustration in FIGS.3A-3C and other figures herein, the discussions regarding eye 210 may beapplied to both eyes 210 and 220 of a viewer.

With continued reference to FIGS. 3A-3C, light from an object that theviewer's eyes are fixated on may have different degrees of wavefrontdivergence. Due to the different amounts of wavefront divergence, thelight may be focused differently by the lens of the eye, which in turnmay require the lens to assume different shapes to form a focused imageon the retina of the eye. Where a focused image is not formed on theretina, the resulting retinal blur acts as a cue to accommodation thatcauses a change in the shape of the lens of the eye until a focusedimage is formed on the retina. For example, the cue to accommodation maytrigger the ciliary muscles surrounding the lens of the eye to relax orcontract, thereby modulating the force applied to the suspensoryligaments holding the lens, thus causing the shape of the lens of theeye to change until retinal blur of an object of fixation is eliminatedor minimized, thereby forming a focused image of the object of fixationon the retina (e.g., fovea) of the eye. The process by which the lens ofthe eye changes shape may be referred to as accommodation, and the shapeof the lens of the eye required to form a focused image of the object offixation on the retina (e.g., fovea) of the eye may be referred to as anaccommodative state.

With reference now to FIG. 4A, a representation of theaccommodation-vergence response of the human visual system isillustrated. The movement of the eyes to fixate on an object causes theeyes to receive light from the object, with the light forming an imageon each of the retinas of the eyes. The presence of retinal blur in theimage formed on the retina may provide a cue to accommodation, and therelative locations of the image on the retinas may provide a cue tovergence. The cue to accommodation causes accommodation to occur,resulting in the lenses of the eyes each assuming a particularaccommodative state that forms a focused image of the object on theretina (e.g., fovea) of the eye. On the other hand, the cue to vergencecauses vergence movements (rotation of the eyes) to occur such that theimages formed on each retina of each eye are at corresponding retinalpoints that maintain single binocular vision. In these positions, theeyes may be said to have assumed a particular vergence state. Withcontinued reference to FIG. 4A, accommodation may be understood to bethe process by which the eye achieves a particular accommodative state,and vergence may be understood to be the process by which the eyeachieves a particular vergence state. As indicated in FIG. 4A, theaccommodative and vergence states of the eyes may change if the userfixates on another object. For example, the accommodated state maychange if the user fixates on a new object at a different depth on thez-axis.

Without being limited by theory, it is believed that viewers of anobject may perceive the object as being “three-dimensional” due to acombination of vergence and accommodation. As noted above, vergencemovements (e.g., rotation of the eyes so that the pupils move toward oraway from each other to converge the lines of sight of the eyes tofixate upon an object) of the two eyes relative to each other areclosely associated with accommodation of the lenses of the eyes. Undernormal conditions, changing the shapes of the lenses of the eyes tochange focus from one object to another object at a different distancewill automatically cause a matching change in vergence to the samedistance, under a relationship known as the “accommodation-vergencereflex.” Likewise, a change in vergence will trigger a matching changein lens shape under normal conditions.

With reference now to FIG. 4B, examples of different accommodative andvergence states of the eyes are illustrated. The pair of eyes 222 a isfixated on an object at optical infinity, while the pair eyes 222 b arefixated on an object 221 at less than optical infinity. Notably, thevergence states of each pair of eyes is different, with the pair of eyes222 a directed straight ahead, while the pair of eyes 222 converge onthe object 221. The accommodative states of the eyes forming each pairof eyes 222 a and 222 b are also different, as represented by thedifferent shapes of the lenses 210 a, 220 a.

Undesirably, many users of conventional “3-D” display systems find suchconventional systems to be uncomfortable or may not perceive a sense ofdepth at all due to a mismatch between accommodative and vergence statesin these displays. As noted above, many stereoscopic or “3-D” displaysystems display a scene by providing slightly different images to eacheye. Such systems are uncomfortable for many viewers, since they, amongother things, simply provide different presentations of a scene andcause changes in the vergence states of the eyes, but without acorresponding change in the accommodative states of those eyes. Rather,the images are shown by a display at a fixed distance from the eyes,such that the eyes view all the image information at a singleaccommodative state. Such an arrangement works against the“accommodation-vergence reflex” by causing changes in the vergence statewithout a matching change in the accommodative state. This mismatch isbelieved to cause viewer discomfort. Display systems that provide abetter match between accommodation and vergence may form more realisticand comfortable simulations of three-dimensional imagery.

Without being limited by theory, it is believed that the human eyetypically may interpret a finite number of depth planes to provide depthperception. Consequently, a highly believable simulation of perceiveddepth may be achieved by providing, to the eye, different presentationsof an image corresponding to each of these limited numbers of depthplanes. In some embodiments, the different presentations may provideboth cues to vergence and matching cues to accommodation, therebyproviding physiologically correct accommodation-vergence matching.

With continued reference to FIG. 4B, two depth planes 240, correspondingto different distances in space from the eyes 210, 220, are illustrated.For a given depth plane 240, vergence cues may be provided by thedisplaying of images of appropriately different perspectives for eacheye 210, 220. In addition, for a given depth plane 240, light formingthe images provided to each eye 210, 220 may have a wavefront divergencecorresponding to a light field produced by a point at the distance ofthat depth plane 240.

In the illustrated embodiment, the distance, along the z-axis, of thedepth plane 240 containing the point 221 is 1 m. As used herein,distances or depths along the z-axis may be measured with a zero-pointlocated at the exit pupils of the user's eyes. Thus, a depth plane 240located at a depth of 1 m corresponds to a distance of 1 m away from theexit pupils of the user's eyes, on the optical axis of those eyes withthe eyes directed towards optical infinity. As an approximation, thedepth or distance along the z-axis may be measured from the display infront of the user's eyes (e.g., from the surface of a waveguide), plus avalue for the distance between the device and the exit pupils of theuser's eyes. That value may be called the eye relief and corresponds tothe distance between the exit pupil of the user's eye and the displayworn by the user in front of the eye. In practice, the value for the eyerelief may be a normalized value used generally for all viewers. Forexample, the eye relief may be assumed to be 20 mm and a depth planethat is at a depth of 1 m may be at a distance of 980 mm in front of thedisplay.

With reference now to FIGS. 4C and 4D, examples of matchedaccommodation-vergence distances and mismatched accommodation-vergencedistances are illustrated, respectively. As illustrated in FIG. 4C, thedisplay system may provide images of a virtual object to each eye 210,220. The images may cause the eyes 210, 220 to assume a vergence statein which the eyes converge on a point 15 on a depth plane 240. Inaddition, the images may be formed by a light having a wavefrontcurvature corresponding to real objects at that depth plane 240. As aresult, the eyes 210, 220 assume an accommodative state in which theimages are in focus on the retinas of those eyes. Thus, the user mayperceive the virtual object as being at the point 15 on the depth plane240.

It will be appreciated that each of the accommodative and vergencestates of the eyes 210, 220 are associated with a particular distance onthe z-axis. For example, an object at a particular distance from theeyes 210, 220 causes those eyes to assume particular accommodativestates based upon the distances of the object. The distance associatedwith a particular accommodative state may be referred to as theaccommodation distance, A_(d). Similarly, there are particular vergencedistances, V_(d), associated with the eyes in particular vergencestates, or positions relative to one another. Where the accommodationdistance and the vergence distance match, the relationship betweenaccommodation and vergence may be said to be physiologically correct.This is considered to be the most comfortable scenario for a viewer.

In stereoscopic displays, however, the accommodation distance and thevergence distance may not always match. For example, as illustrated inFIG. 4D, images displayed to the eyes 210, 220 may be displayed withwavefront divergence corresponding to depth plane 240, and the eyes 210,220 may assume a particular accommodative state in which the points 15a, 15 b on that depth plane are in focus. However, the images displayedto the eyes 210, 220 may provide cues for vergence that cause the eyes210, 220 to converge on a point 15 that is not located on the depthplane 240. As a result, the accommodation distance corresponds to thedistance from the exit pupils of the eyes 210, 220 to the depth plane240, while the vergence distance corresponds to the larger distance fromthe exit pupils of the eyes 210, 220 to the point 15, in someembodiments. The accommodation distance is different from the vergencedistance. Consequently, there is an accommodation-vergence mismatch.Such a mismatch is considered undesirable and may cause discomfort inthe user. It will be appreciated that the mismatch corresponds todistance (e.g., V_(d)-A_(d)) and may be characterized using diopters.

In some embodiments, it will be appreciated that a reference point otherthan exit pupils of the eyes 210, 220 may be utilized for determiningdistance for determining accommodation-vergence mismatch, so long as thesame reference point is utilized for the accommodation distance and thevergence distance. For example, the distances could be measured from thecornea to the depth plane, from the retina to the depth plane, from theeyepiece (e.g., a waveguide of the display device) to the depth plane,and so on.

Without being limited by theory, it is believed that users may stillperceive accommodation-vergence mismatches of up to about 0.25 diopter,up to about 0.33 diopter, and up to about 0.5 diopter as beingphysiologically correct, without the mismatch itself causing significantdiscomfort. In some embodiments, display systems disclosed herein (e.g.,the display system 250, FIG. 6) present images to the viewer havingaccommodation-vergence mismatch of about 0.5 diopter or less. In someother embodiments, the accommodation-vergence mismatch of the imagesprovided by the display system is about 0.33 diopter or less. In yetother embodiments, the accommodation-vergence mismatch of the imagesprovided by the display system is about 0.25 diopter or less, includingabout 0.1 diopter or less.

FIG. 5 illustrates aspects of an approach for simulatingthree-dimensional imagery by modifying wavefront divergence. The displaysystem includes a waveguide 270 that is configured to receive light 770that is encoded with image information, and to output that light to theuser's eye 210. The waveguide 270 may output the light 650 with adefined amount of wavefront divergence corresponding to the wavefrontdivergence of a light field produced by a point on a desired depth plane240. In some embodiments, the same amount of wavefront divergence isprovided for all Objects presented on that depth plane. In addition, itwill be illustrated that the other eye of the user may be provided withimage information from a similar waveguide.

In some embodiments, a single waveguide may be configured to outputlight with a set amount of wavefront divergence corresponding to asingle or limited number of depth planes and/or the waveguide may beconfigured to output light of a limited range of wavelengths.Consequently, in some embodiments, a plurality or stack of waveguidesmay be utilized to provide different amounts of wavefront divergence fordifferent depth planes and/or to output light of different ranges ofwavelengths. As used herein, it will be appreciated at a depth plane mayfollow the contours of a flat or a curved surface. In some embodiments,advantageously for simplicity, the depth planes may follow the contoursof flat surfaces.

FIG. 6 illustrates an example of a waveguide stack for outputting imageinformation to a user. A display system 250 includes a stack ofwaveguides, or stacked waveguide assembly, 260 that may be utilized toprovide three-dimensional perception to the eye/brain using a pluralityof waveguides 270, 280, 290, 300, 310. It will be appreciated that thedisplay system 250 may be considered a light field display in someembodiments. In addition, the waveguide assembly 260 may also bereferred to as an eyepiece.

In some embodiments, the display system 250 may be configured to providesubstantially continuous cues to vergence and multiple discrete cues toaccommodation. The cues to vergence may be provided by displayingdifferent images to each of the eyes of the user, and the cues toaccommodation may be provided by outputting the light that forms theimages with selectable discrete amounts of wavefront divergence. Statedanother way, the display system 250 may be configured to output lightwith variable levels of wavefront divergence. In some embodiments, eachdiscrete level of wavefront divergence corresponds to a particular depthplane and may be provided by a particular one of the waveguides 270,280, 290, 300, 310.

With continued reference to FIG. 6, the waveguide assembly 260 may alsoinclude a plurality of features 320, 330, 340, 350 between thewaveguides. In some embodiments, the features 320, 330, 340, 350 may beone or more lenses. The waveguides 270, 280, 290, 300, 310 and/or theplurality of lenses 320, 330, 340, 350 may be configured to send imageinformation to the eye with various levels of wavefront curvature orlight ray divergence. Each waveguide level may be associated with aparticular depth plane and may be configured to output image informationcorresponding to that depth plane. Image injection devices 360, 370,380, 390, 400 may function as a source of light for the waveguides andmay be utilized to inject image information into the waveguides 270,280, 290, 300, 310, each of which may be configured, as describedherein, to distribute incoming light across each respective waveguide,for output toward the eye 210. Light exits an output surface 410, 420,430, 440, 450 of the image injection devices 360, 370, 380, 390, 400 andis injected into a corresponding input surface 460, 470, 480, 490, 500of the waveguides 270, 280, 290, 300, 310. In some embodiments, each ofthe input surfaces 460, 470, 480, 490, 500 may be an edge of acorresponding waveguide, or may be part of a major surface of thecorresponding waveguide (that is, one of the waveguide surfaces directlyfacing the world 510 or the viewer's eye 210). In some embodiments, asingle beam of light (e.g. a collimated beam) may be injected into eachwaveguide to output an entire field of cloned collimated beams that aredirected toward the eye 210 at particular angles and amounts ofdivergence) corresponding to the depth plane associated with aparticular waveguide. In some embodiments, a single one of the imageinjection devices 360, 370, 380, 390, 400 may be associated with andinject light into a plurality (e.g., three) of the waveguides 270, 280,290, 300, 310.

In some embodiments, the image injection devices 360, 370, 380, 390, 400are discrete displays that each produce image information for injectioninto a corresponding waveguide 270, 280, 290, 300, 310, respectively. Insome other embodiments, the image injection devices 360, 370, 380, 390,400 are the output ends of a single multiplexed display which may, e.g.,pipe image information via one or more optical conduits (such as fiberoptic cables) to each of the image injection devices 360, 370, 380, 390,400. It will be appreciated that the image information provided by theimage injection devices 360, 370, 380, 390, 400 may include light ofdifferent wavelengths, or colors (e.g., different component colors, asdiscussed herein).

In some embodiments, the light injected into the waveguides 270, 280,290, 300, 310 is provided by a light projector system 520, whichcomprises a light module 530, which may include a light emitter, such asa light emitting diode (LED). The light from the light module 530 may bedirected to and modified by a light modulator 540, e.g., a spatial lightmodulator, via a beam splitter 550. The light modulator 540 may beconfigured to change the perceived intensity of the light injected intothe waveguides 270, 280, 290, 300, 310 to encode the light with imageinformation. Examples of spatial light modulators include liquid crystaldisplays (LCD) including a liquid crystal on silicon (LCOS) displays. Itwill be appreciated that the image injection devices 360, 370, 380, 390,400 are illustrated schematically and, in some embodiments, these imageinjection devices may represent different light paths and locations in acommon projection system configured to output light into associated onesof the waveguides 270, 280, 290, 300, 310. In some embodiments, thewaveguides of the waveguide assembly 260 may function as ideal lenswhile relaying light injected into the waveguides out to the user'seyes. In this conception, the object may be the spatial light modulator540 and the image may be the image on the depth plane.

In some embodiments, the display system 250 may be a scanning fiberdisplay comprising one or more scanning fibers configured to projectlight in various patterns (e.g., raster scan, spiral scan, Lissajouspatterns, etc.) into one or more waveguides 270, 280, 290, 300, 310 andultimately to the eye 210 of the viewer. In some embodiments, theillustrated image injection devices 360, 370, 380, 390, 400 mayschematically represent a single scanning fiber or a bundle of scanningfibers configured to inject light into one or a plurality of thewaveguides 270, 280, 290, 300, 310. In some other embodiments, theillustrated image injection devices 360, 370, 380, 390, 400 mayschematically represent a plurality of scanning fibers or a plurality ofbundles of scanning fibers, each of which are configured to inject lightinto an associated one of the waveguides 270, 280, 290, 300, 310. Itwill be appreciated that one or more optical fibers may be configured totransmit light from the light module 530 to the one or more waveguides270, 280, 290, 300, 310. It will be appreciated that one or moreintervening optical structures may be provided between the scanningfiber, or fibers, and the one or more waveguides 270, 280, 290, 300, 310to, e.g., redirect light exiting the scanning fiber into the one or morewaveguides 270, 280, 290, 300, 310.

A controller 560 controls the operation of one or more of the stackedwaveguide assembly 260, including operation of the image injectiondevices 360, 370, 380, 390, 400, the light source 530, and the lightmodulator 540. In some embodiments, the controller 560 is part of thelocal data processing module 140. The controller 560 includesprogramming (e.g., instructions in a non-transitory medium) thatregulates the timing and provision of image information to thewaveguides 270, 280, 290, 300, 310 according to, e.g., any of thevarious schemes disclosed herein. In some embodiments, the controllermay be a single integral device, or a distributed system connected bywired or wireless communication channels. The controller 560 may be partof the processing modules 140 or 150 (FIG. 9D) in some embodiments.

With continued reference to FIG. 6, the waveguides 270, 280, 290, 300,310 may be configured to propagate light within each respectivewaveguide by total internal reflection (TIR). The waveguides 270, 280,290, 300, 310 may each be planar or have another shape (e.g., curved),with major top and bottom surfaces and edges extending between thosemajor top and bottom surfaces. In the illustrated configuration, thewaveguides 270, 280, 290, 300, 310 may each include out-coupling opticalelements 570, 580, 590, 600, 610 that are configured to extract lightout of a waveguide by redirecting the light, propagating within eachrespective waveguide, out of the waveguide to output image informationto the eye 210. Extracted light may also be referred to as out-coupledlight and the out-coupling optical elements light may also be referredto as light extracting optical elements. An extracted beam of light maybe outputted by the waveguide at locations at which the lightpropagating in the waveguide strikes a light extracting optical element.The out-coupling optical elements 570, 580, 590, 600, 610 may, forexample, be gratings, including diffractive optical features, asdiscussed further herein. While illustrated disposed at the bottom majorsurfaces of the waveguides 270, 280, 290, 300, 310, for ease ofdescription and drawing clarity, in some embodiments, the out-couplingoptical elements 570, 580, 590, 600, 610 may be disposed at the topand/or bottom major surfaces, and/or may be disposed directly in thevolume of the waveguides 270, 280, 290, 300, 310, as discussed furtherherein. In some embodiments, the out-coupling optical elements 570, 580,590, 600, 610 may be formed in a layer of material that is attached to atransparent substrate to form the waveguides 270, 280, 290, 300, 310. Insome other embodiments, the waveguides 270, 280, 290, 300, 310 may be amonolithic piece of material and the out-coupling optical elements 570,580, 590, 600, 610 may be formed on a surface and/or in the interior ofthat piece of material. As described herein, in some embodiments, theout-coupling optical elements 570, 580, 590, 600, 610 may be integratedwith surface portions of the waveguides 270, 280, 290, 300, 310.

With continued reference to FIG. 6, as discussed herein, each waveguide270, 280, 290, 300, 310 is configured to output light to form an imagecorresponding to a particular depth plane. For example, the waveguide270 nearest the eye may be configured to deliver collimated light (whichwas injected into such waveguide 270), to the eye 210. The collimatedlight may be representative of the optical infinity focal plane. Thenext waveguide up 280 may be configured to send out collimated lightwhich passes through the first lens 350 (e.g., a negative lens) beforeit may reach the eye 210; such first lens 350 may be configured tocreate a slight convex wavefront curvature so that the eye/braininterprets light coming from that next waveguide up 280 as coming from afirst focal plane closer inward toward the eye 210 from opticalinfinity. Similarly, the third up waveguide 290 passes its output lightthrough both the first 350 and second 340 lenses before reaching the eye210; the combined optical power of the first 350 and second 340 lensesmay be configured to create another incremental amount of wavefrontcurvature so that the eye/brain interprets light coming from the thirdwaveguide 290 as coming from a second focal plane that is even closerinward toward the person from optical infinity than was light from thenext waveguide up 280.

The other waveguide layers 300, 310 and lenses 330, 320 are similarlyconfigured, with the highest waveguide 310 in the stack sending itsoutput through all of the lenses between it and the eye for an aggregatefocal power representative of the closest focal plane to the person. Tocompensate for the stack of lenses 320, 330, 340, 350 whenviewing/interpreting light coming from the world 510 on the other sideof the stacked waveguide assembly 260, a compensating lens or lens layer620 may be disposed at the top of the stack to compensate for theaggregate power of the lens stack 320, 330, 340, 350 below. Such aconfiguration provides as many perceived focal planes as there areavailable waveguide/lens pairings. Both the out-coupling opticalelements of the waveguides and the focusing aspects of the lenses may bestatic (i.e., not dynamic or electro-active). In some alternativeembodiments, either or both may be dynamic using electro-activefeatures.

In some embodiments, two or more of the waveguides 270, 280, 290, 300,310 may have the same associated depth plane. For example, multiplewaveguides 270, 280, 290, 300, 310 may be configured to output imagesset to the same depth plane, or multiple subsets of the waveguides 270,280, 290, 300, 310 may be configured to output images set to the sameplurality of depth planes, with one set for each depth plane. This mayprovide advantages for forming a tiled image to provide an expandedfield of view at those depth planes.

With continued reference to FIG. 6, the out-coupling optical elements570, 580, 590, 600, 610 may be configured to both redirect light out oftheir respective waveguides and to output this light with theappropriate amount of divergence or collimation for a particular depthplane associated with the waveguide. As a result, waveguides havingdifferent associated depth planes may have different configurations ofout-coupling optical elements 570, 580, 590, 600, 610, which outputlight with a different amount of divergence depending on the associateddepth plane. In some embodiments, the light extracting optical elements570, 580, 590, 600, 610 may be volumetric or surface features, which maybe configured to output light at specific angles. For example, the lightextracting optical elements 570, 580, 590, 600, 610 may be volumeholograms, surface holograms, and/or diffraction gratings. In someembodiments, the light extracting optical elements 570, 580, 590, 600,610 may be gratings integrated with surface portions of the waveguides270, 280, 290, 300, 310.

In some embodiments, the out-coupling optical elements 570, 580, 590,600, 610 are diffractive features that form a diffraction pattern, or“diffractive optical element” (also referred to herein as a “DOE”).Preferably, the DOE's have a sufficiently low diffraction efficiency sothat only a portion of the light of the beam is deflected away towardthe eye 210 with each intersection of the DOE, while the rest continuesto move through a waveguide via TIR. The light carrying the imageinformation is thus divided into a number of related exit beams thatexit the waveguide at a multiplicity of locations and the result is afairly uniform pattern of exit emission toward the eye 210 for thisparticular collimated beam bouncing around within a waveguide.

In some embodiments, one or more DOEs may be switchable between “on”states in which they actively diffract, and “off” states in which theydo not significantly diffract. For instance, a switchable DOE maycomprise a layer of polymer dispersed liquid crystal, in whichmicrodroplets comprise a diffraction pattern in a host medium, and therefractive index of the microdroplets may be switched to substantiallymatch the refractive index of the host material (in which case thepattern does not appreciably diffract incident light) or themicrodroplet may be switched to an index that does not match that of thehost medium (in which case the pattern actively diffracts incidentlight).

In some embodiments, a camera assembly 630 (e.g., a digital camera,including visible light and infrared light cameras) may be provided tocapture images of the eye 210 and/or tissue around the eye 210 to, e.g.,detect user inputs and/or to monitor the physiological state of theuser. As used herein, a camera may be any image capture device. In someembodiments, the camera assembly 630 may include an image capture deviceand a light source to project light (e.g., infrared light) to the eye,which may then be reflected by the eye and detected by the image capturedevice. In some embodiments, the camera assembly 630 may be attached tothe frame 80 (FIG. 9D) and may be in electrical communication with theprocessing modules 140 and/or 150, which may process image informationfrom the camera assembly 630. In some embodiments, one camera assembly630 may be utilized for each eye, to separately monitor each eye.

With reference now to FIG. 7, an example of exit beams outputted by awaveguide is shown. One waveguide is illustrated, but it will beappreciated that other waveguides in the waveguide assembly 260 (FIG. 6)may function similarly, where the waveguide assembly 260 includesmultiple waveguides. Light 640 is injected into the waveguide 270 at theinput surface 460 of the waveguide 270 and propagates within thewaveguide 270 by TIR. At points where the light 640 impinges on the DOE570, a portion of the light exits the waveguide as exit beams 650. Theexit beams 650 are illustrated as substantially parallel but, asdiscussed herein, they may also be redirected to propagate to the eye210 at an angle (e.g., forming divergent exit beams), depending on thedepth plane associated with the waveguide 270. It will be appreciatedthat substantially parallel exit beams may be indicative of a waveguidewith out-coupling optical elements that out-couple light to four imagesthat appear to be set on a depth plane at a large distance (e.g.,optical infinity) from the eye 210. Other waveguides or other sets ofout-coupling optical elements may output an exit beam pattern that ismore divergent, which would require the eye 210 to accommodate to acloser distance to bring it into focus on the retina and would beinterpreted by the brain as light from a distance closer to the eye 210than optical infinity.

In some embodiments, a full color image may be formed at each depthplane by overlaying images in each of the component colors, e.g., threeor more component colors. FIG. 8 illustrates an example of a stackedwaveguide assembly in which each depth plane includes images formedusing multiple different component colors. The illustrated embodimentshows depth planes 240 a-240 f, although more or fewer depths are alsocontemplated. Each depth plane may have three or more component colorimages associated with it, including: a first image of a first color, G;a second image of a second color, R; and a third image of a third color,B. Different depth planes are indicated in the figure by differentnumbers for diopters (dpt) following the letters G, R, and B. Just asexamples, the numbers following each of these letters indicate diopters(1/m), or inverse distance of the depth plane from a viewer, and eachbox in the figures represents an individual component color image. Insome embodiments, to account for differences in the eye's focusing oflight of different wavelengths, the exact placement of the depth planesfor different component colors may vary. For example, differentcomponent color images for a given depth plane may be placed on depthplanes corresponding to different distances from the user. Such anarrangement may increase visual acuity and user comfort and/or maydecrease chromatic aberrations.

In some embodiments, light of each component color may be outputted by asingle dedicated waveguide and, consequently, each depth plane may havemultiple waveguides associated with it. In such embodiments, each box inthe figures including the letters G, R, or B may be understood torepresent an individual waveguide, and three waveguides may be providedper depth plane where three component color images are provided perdepth plane. While the waveguides associated with each depth plane areshown adjacent to one another in this drawing for ease of description,it will be appreciated that, in a physical device, the waveguides mayall be arranged in a stack with one waveguide per level. In some otherembodiments, multiple component colors may be outputted by the samewaveguide, such that, e.g., only a single waveguide may be provided perdepth plane.

With continued reference to FIG. 8, in some embodiments, G is the colorgreen, R is the color red, and B is the color blue. In some otherembodiments, other colors associated with other wavelengths of light,including magenta and cyan, may be used in addition to or may replaceone or more of red, green, or blue.

It will be appreciated that references to a given color of lightthroughout this disclosure will be understood to encompass light of oneor more wavelengths within a range of wavelengths of light that areperceived by a viewer as being of that given color. For example, redlight may include light of one or more wavelengths in the range of about620-780 nm, green light may include light of one or more wavelengths inthe range of about 492-577 nm, and blue light may include light of oneor more wavelengths in the range of about 435-493 nm.

In some embodiments, the light source 530 (FIG. 6) may be configured toemit light of one or more wavelengths outside the visual perceptionrange of the viewer, for example, infrared and/or ultravioletwavelengths. In addition, the in-coupling, out-coupling, and other lightredirecting structures of the waveguides of the display 250 may beconfigured to direct and emit this light out of the display towards theuser's eye 210 e.g., for imaging and/or user stimulation applications.

With reference now to FIG. 9A, in some embodiments, light impinging on awaveguide may need to be redirected to in-couple that light into thewaveguide. An in-coupling optical element may be used to redirect andin-couple the light into its corresponding waveguide. FIG. 9Aillustrates a cross-sectional side view of an example of a plurality orset 660 of stacked waveguides that each includes an in-coupling opticalelement. The waveguides may each be configured to output light of one ormore different wavelengths, or one or more different ranges ofwavelengths. It will be appreciated that the stack 660 may correspond tothe stack 260 (FIG. 6) and the illustrated waveguides of the stack 660may correspond to part of the plurality of waveguides 270, 280, 290,300, 310, except that light from one or more of the image injectiondevices 360, 370, 380, 390, 400 is injected into the waveguides from aposition that requires light to be redirected for in-coupling.

The illustrated set 660 of stacked waveguides includes waveguides 670,680, and 690. Each waveguide includes an associated in-coupling opticalelement (which may also be referred to as a light input area on thewaveguide), with, e.g., in-coupling optical element 700 disposed on amajor surface (e.g., an upper major surface) of waveguide 670,in-coupling optical element 710 disposed on a major surface (e.g., anupper major surface) of waveguide 680, and in-coupling optical element720 disposed on a major surface (e.g., an upper major surface) ofwaveguide 690. In some embodiments, one or more of the in-couplingoptical elements 700, 710, 720 may be disposed on the bottom majorsurface of the respective waveguide 670, 680, 690 (particularly wherethe one or more in-coupling optical elements are reflective, deflectingoptical elements). As illustrated, the in-coupling optical elements 700,710, 720 may be disposed on the upper major surface of their respectivewaveguide 670, 680, 690 (or the top of the next lower waveguide),particularly where those in-coupling optical elements are transmissive,deflecting optical elements. In some embodiments, the in-couplingoptical elements 700, 710, 720 may be disposed in the body of therespective waveguide 670, 680, 690. In some embodiments, as discussedherein, the in-coupling optical elements 700, 710, 720 are wavelengthselective, such that they selectively redirect one or more wavelengthsof light, while transmitting other wavelengths of light. Whileillustrated on one side or corner of their respective waveguide 670,680, 690, it will be appreciated that the in-coupling optical elements700, 710, 720 may be disposed in other areas of their respectivewaveguide 670, 680, 690 in some embodiments. As described herein, insome embodiments, the in-coupling optical elements 700, 710, 720 may beintegrated with surface portions of the waveguides 670, 680, 690.

As illustrated, the in-coupling optical elements 700, 710, 720 may belaterally offset from one another. In some embodiments, each in-couplingoptical element may be offset such that it receives light without thatlight passing through another in-coupling optical element. For example,each in-coupling optical element 700, 710, 720 may be configured toreceive light from a different image injection device 360, 370, 380,390, and 400 as shown in FIG. 6, and may be separated (e.g., laterallyspaced apart) from other in-coupling optical elements 700, 710, 720 suchthat it substantially does not receive light from the other ones of thein-coupling optical elements 700, 710, 720.

Each waveguide also includes associated light distributing elements,with, e.g., light distributing elements 730 disposed on a major surface(e.g., a top major surface) of waveguide 670, light distributingelements 740 disposed on a major surface (e.g., a top major surface) ofwaveguide 680, and light distributing elements 750 disposed on a majorsurface (e.g., a top major surface) of waveguide 690. In some otherembodiments, the light distributing elements 730, 740, 750, may bedisposed on a bottom major surface of associated waveguides 670, 680,690, respectively. In some other embodiments, the light distributingelements 730, 740, 750, may be disposed on both top and bottom majorsurface of associated waveguides 670, 680, 690, respectively; or thelight distributing elements 730, 740, 750, may be disposed on differentones of the top and bottom major surfaces in different associatedwaveguides 670, 680, 690, respectively. As described herein, in someembodiments, the light distributing elements 730, 740, 750 may beintegrated with surface portions of the waveguides 670, 680, 690.

The waveguides 670, 680, 690 may be spaced apart and separated by, e.g.,gas, liquid, and/or solid layers of material. For example, asillustrated, layer 760 a may separate waveguides 670 and 680; and layer760 b may separate waveguides 680 and 690. In some embodiments, thelayers 760 a and 760 b are formed of low refractive index materials(that is, materials having a lower refractive index than the materialforming the immediately adjacent one of waveguides 670, 680, 690).Preferably, the refractive index of the material forming the layers 760a, 760 b is 0.05 or more, or 0.10 or less than the refractive index ofthe material forming the waveguides 670, 680, 690. Advantageously, thelower refractive index layers 760 a, 760 b may function as claddinglayers that facilitate total internal reflection (TIR) of light throughthe waveguides 670, 680, 690 (e.g., TIR between the top and bottom majorsurfaces of each waveguide). In some embodiments, the layers 760 a, 760b are formed of air. While not illustrated, it will be appreciated thatthe top and bottom of the illustrated set 660 of waveguides may includeimmediately neighboring cladding layers.

Preferably, for ease of manufacturing and other considerations, thematerial forming the waveguides 670, 680, 690 are similar or the same,and the material forming the layers 760 a, 760 b are similar or thesame. In some embodiments, the material forming the waveguides 670, 680,690 may be different between one or more waveguides, and/or the materialforming the layers 760 a, 760 b may be different, while still holding tothe various refractive index relationships noted above.

With continued reference to FIG. 9A, light rays 770, 780, 790 areincident on the set 660 of waveguides. It will be appreciated that thelight rays 770, 780, 790 may be injected into the waveguides 670, 680,690 by one or more image injection devices 360, 370, 380, 390, 400 (FIG.6).

In some embodiments, the light rays 770, 780, 790 have differentproperties, e.g., different wavelengths or different ranges ofwavelengths, which may correspond to different colors. The in-couplingoptical elements 700, 710, 720 each deflect the incident light such thatthe light propagates through a respective one of the waveguides 670,680, 690 by TIR. In some embodiments, the in-coupling optical elements700, 710, 720 each selectively deflect one or more particularwavelengths of light, while transmitting other wavelengths to anunderlying waveguide and associated in-coupling optical element.

For example, in-coupling optical element 700 may be configured todeflect ray 770, which has a first wavelength or range of wavelengths,while transmitting rays 780 and 790, which have different second andthird wavelengths or ranges of wavelengths, respectively. Thetransmitted ray 780 impinges on and is deflected by the in-couplingoptical element 710, which is configured to deflect light of a secondwavelength or range of wavelengths. The ray 790 is deflected by thein-coupling optical element 720, which is configured to selectivelydeflect light of third wavelength or range of wavelengths.

With continued reference to FIG. 9A, the deflected light rays 770, 780,790 are deflected so that they propagate through a correspondingwaveguide 670, 680, 690; that is, the in-coupling optical elements 700,710, 720 of each waveguide deflects light into that correspondingwaveguide 670, 680, 690 to in-couple light into that correspondingwaveguide. The light rays 770, 780, 790 are deflected at angles thatcause the light to propagate through the respective waveguide 670, 680,690 by TIR. The light rays 770, 780, 790 propagate through therespective waveguide 670, 680, 690 by TIR until impinging on thewaveguide's corresponding light distributing elements 730, 740, 750.

With reference now to FIG. 9B, a perspective view of an example of theplurality of stacked waveguides of FIG. 9A is illustrated. As notedabove, the in-coupled light rays 770, 780, 790, are deflected by thein-coupling optical elements 700, 710, 720, respectively, and thenpropagate by TIR within the waveguides 670, 680, 690, respectively. Thelight rays 770, 780, 790 then impinge on the light distributing elements730, 740, 750, respectively. The light distributing elements 730, 740,750 deflect the light rays 770, 780, 790 so that they propagate towardsthe out-coupling optical elements 800, 810, 820, respectively.

In some embodiments, the light distributing elements 730, 740, 750 areorthogonal pupil expanders (OPE's). In some embodiments, the OPE'sdeflect or distribute light to the out-coupling optical elements 800,810, 820 and, in some embodiments, may also increase the beam or spotsize of this light as it propagates to the out-coupling opticalelements. In some embodiments, the light distributing elements 730, 740,750 may be omitted and the in-coupling optical elements 700, 710, 720may be configured to deflect light directly to the out-coupling opticalelements 800, 810, 820. For example, with reference to FIG. 9A, thelight distributing elements 730, 740, 750 may be replaced without-coupling optical elements 800, 810, 820, respectively. In someembodiments, the out-coupling optical elements 800, 810, 820 are exitpupils (EP's) or exit pupil expanders (EPE's) that direct light in aviewer's eye 210 (FIG. 7). It will be appreciated that the OPE's may beconfigured to increase the dimensions of the eye box in at least oneaxis and the EPE's may be to increase the eye box in an axis crossing,e.g., orthogonal to, the axis of the OPEs. For example, each OPE may beconfigured to redirect a portion of the light striking the OPE to an EPEof the same waveguide, while allowing the remaining portion of the lightto continue to propagate down the waveguide. Upon impinging on the OPEagain, another portion of the remaining light is redirected to the EPE,and the remaining portion of that portion continues to propagate furtherdown the waveguide, and so on. Similarly, upon striking the EPE, aportion of the impinging light is directed out of the waveguide towardsthe user, and a remaining portion of that light continues to propagatethrough the waveguide until it strikes the EP again, at Which timeanother portion of the impinging light is directed out of the waveguide,and so on. Consequently, a single beam of incoupled light may be“replicated” each time a portion of that light is redirected by an OPEor EPE, thereby forming a field of cloned beams of light, as shown inFIG. 6. In some embodiments, the OPE and/or EPE may be configured tomodify a size of the beams of light.

Accordingly, with reference to FIGS. 9A and 9B, in some embodiments, theset 660 of waveguides includes waveguides 670, 680, 690; in-couplingoptical elements 700, 710, 720; light distributing elements (e.g.,OPE's) 730, 740, 750; and out-coupling optical elements (e.g., EP's)800, 810, 820 for each component color. The waveguides 670, 680, 690 maybe stacked with an air gap/cladding layer between each one. Thein-coupling optical elements 700, 710, 720 redirect or deflect incidentlight (with different in-coupling optical elements receiving light ofdifferent wavelengths) into its waveguide. The light then propagates atan angle which will result in TIR within the respective waveguide 670,680, 690. In the example shown, light ray 770 (e.g., blue light) isdeflected by the first in-coupling optical element 700, and thencontinues to bounce down the waveguide, interacting with the lightdistributing element (e.g., OPE's) 730 and then the out-coupling opticalelement (e.g., EPs) 800, in a manner described earlier. The light rays780 and 790 (e.g., green and red light, respectively) will pass throughthe waveguide 670, with light ray 780 impinging on and being deflectedby in-coupling optical element 710. The light ray 780 then bounces downthe waveguide 680 via TIR, proceeding on to its light distributingelement (e.g., OPEs) 740 and then the out-coupling optical element(e.g., EP's) 810. Finally, light ray 790 (e.g., red light) passesthrough the waveguide 690 to impinge on the light in-coupling opticalelements 720 of the waveguide 690. The light in-coupling opticalelements 720 deflect the light ray 790 such that the light raypropagates to light distributing element (e.g., OPEs) 750 by TIR, andthen to the out-coupling optical element (e.g., EPs) 820 by TIR. Theout-coupling optical element 820 then finally out-couples the light ray790 to the viewer, who also receives the out-coupled light from theother waveguides 670, 680.

FIG. 9C illustrates a top-down plan view of an example of the pluralityof stacked waveguides of FIGS. 9A and 9B. As illustrated, the waveguides670, 680, 690, along with each waveguide's associated light distributingelement 730, 740, 750 and associated out-coupling optical element 800,810, 820, may be vertically aligned. However, as discussed herein, thein-coupling optical elements 700, 710, 720 are not vertically aligned;rather, the in-coupling optical elements are preferably non-overlapping(e.g., laterally spaced apart as seen in the top-down view). Asdiscussed further herein, this nonoverlapping spatial arrangementfacilitates the injection of light from different resources intodifferent waveguides on a one-to-one basis, thereby allowing a specificlight source to be uniquely coupled to a specific waveguide. In someembodiments, arrangements including nonoverlapping spatially-separatedin-coupling optical elements may be referred to as a shifted pupilsystem, and the in-coupling optical elements within these arrangementsmay correspond to sub pupils.

FIG. 9D illustrates an example of wearable display system 60 into whichthe various waveguides and related systems disclosed herein may beintegrated. In some embodiments, the display system 60 is the system 250of FIG. 6, with FIG. 6 schematically showing some parts of that system60 in greater detail. For example, the waveguide assembly 260 of FIG. 6may be part of the display 70.

With continued reference to FIG. 9D, the display system 60 includes adisplay 70, and various mechanical and electronic modules and systems tosupport the functioning of that display 70. The display 70 may becoupled to a frame 80, which is wearable by a display system user orviewer 90 and which is configured to position the display 70 in front ofthe eyes of the user 90. The display 70 may be considered eyewear insome embodiments. In some embodiments, a speaker 100 is coupled to theframe 80 and configured to be positioned adjacent the ear canal of theuser 90 (in some embodiments, another speaker, not shown, may optionallybe positioned adjacent the other ear canal of the user to providestereo/shapeable sound control). The display system 60 may also includeone or more microphones 110 or other devices to detect sound. In someembodiments, the microphone is configured to allow the user to provideinputs or commands to the system 60 (e.g., the selection of voice menucommands, natural language questions, etc.), and/or may allow audiocommunication with other persons (e.g., with other users of similardisplay systems. The microphone may further be configured as aperipheral sensor to collect audio data (e.g., sounds from the userand/or environment). In some embodiments, the display system 60 mayfurther include one or more outwardly-directed environmental sensors 112configured to detect objects, stimuli, people, animals, locations, orother aspects of the world around the user. For example, environmentalsensors 112 may include one or more cameras, which may be located, forexample, facing outward so as to capture images similar to at least aportion of an ordinary field of view of the user 90. In someembodiments, the display system may also include a peripheral sensor 120a, which may be separate from the frame 80 and attached to the body ofthe user 90 (e.g., on the head, torso, an extremity, etc. of the user90). The peripheral sensor 120 a may be configured to acquire datacharacterizing a physiological state of the user 90 in some embodiments.For example, the sensor 120 a may be an electrode.

With continued reference to FIG. 9D, the display 70 is operativelycoupled by communications link 130, such as by a wired lead or wirelessconnectivity, to a local data processing module 140 which may be mountedin a variety of configurations, such as fixedly attached to the frame80, fixedly attached to a helmet or hat worn by the user, embedded inheadphones, or otherwise removably attached to the user 90 (e.g., in abackpack-style configuration, in a belt-coupling style configuration).Similarly, the sensor 120 a may be operatively coupled by communicationslink 120 b, e.g., a wired lead or wireless connectivity, to the localprocessor and data module 140. The local processing and data module 140may comprise a hardware processor, as well as digital memory, such asnon-volatile memory (e.g., flash memory or hard disk drives), both ofwhich may be utilized to assist in the processing, caching, and storageof data. Optionally, the local processor and data module 140 may includeone or more central processing units (CPUs), graphics processing units(GPUs), dedicated processing hardware, and so on. The data may includedata a) captured from sensors (which may be, e.g., operatively coupledto the frame 80 or otherwise attached to the user 90), such as imagecapture devices (such as cameras), microphones, inertial measurementunits, accelerometers, compasses, GPS units, radio devices, gyros,and/or other sensors disclosed herein; and/or b) acquired and/orprocessed using remote processing module 150 and/or remote datarepository 160 (including data relating to virtual content), possiblyfor passage to the display 70 after such processing or retrieval. Thelocal processing and data module 140 may be operatively coupled bycommunication links 170, 180, such as via a wired or wirelesscommunication links, to the remote processing module 150 and remote datarepository 160 such that these remote modules 150, 160 are operativelycoupled to each other and available as resources to the local processingand data module 140. In some embodiments, the local processing and datamodule 140 may include one or more of the image capture devices,microphones, inertial measurement units, accelerometers, compasses, GPSunits, radio devices, and/or gyros. In some other embodiments, one ormore of these sensors may be attached to the frame 80, or may bestandalone structures that communicate with the local processing anddata module 140 by wired or wireless communication pathways.

With continued reference to FIG. 9D, in some embodiments, the remoteprocessing module 150 may comprise one or more processors configured toanalyze and process data and/or image information, for instanceincluding one or more central processing units (CPUs), graphicsprocessing units (GPUs), dedicated processing hardware, and so on. Insome embodiments, the remote data repository 160 may comprise a digitaldata storage facility, which may be available through the internet orother networking configuration in a “cloud” resource configuration. Insome embodiments, the remote data repository 160 may include one or moreremote servers, which provide information, e.g., information forgenerating augmented reality content, to the local processing and datamodule 140 and/or the remote processing module 150. In some embodiments,all data is stored and all computations are performed in the localprocessing and data module, allowing fully autonomous use from a remotemodule. Optionally, an outside system (e.g., a system of one or moreprocessors, one or more computers) that includes CPUs, GPUs, and so on,may perform at least a portion of processing (e.g., generating imageinformation, processing data) and provide information to, and receiveinformation from, modules 140, 150, 160, for instance via wireless orwired connections.

Example Waveguides

As described with respect to FIG. 6, light containing image informationcan be provided to an eyepiece (an eyepiece comprising for example, awaveguide assembly 260 comprising waveguides 270, 280, 290, 300, 310) bya light projector system 520 (e.g., by image injection devices 360, 370,380, 390, 400 of the projector system 520). Low coupling efficiency ofthe light between the projector system 520 and the waveguides 270, 280,290, 300, 310 can lower the total efficiency of the waveguide assembly260 and can degrade the overall image quality provided to the viewer.Compared to waveguides used in current display systems, certainimplementations of waveguides described herein can advantageouslyprovide higher coupling efficiency, better image quality, and/or asimpler manufacturing process.

Referring now to FIG. 10, an example waveguide with an integratedin-coupling optical element is illustrated. The example waveguide 1000includes an integrated in-coupling optical element 1030 configured tocouple incident light into the waveguide 1000. The light can propagatethough the waveguide 1000 via total internal reflection. One or morelight distributing elements 1035 can direct the light towards one ormore out-coupling optical elements 1040, which can extract and directthe light out of the waveguide 1000 and into a viewer's eyes.

In various implementations, the waveguide 1000 can include a layer 1005comprising a substantially optically transparent material. In someimplementations, the layer 1005 can be highly transparent to wavelengthsof light in the visible spectrum, e.g., 390-700 nm. For example, thelayer 1005 can transmit from about 85% to about 100%, from about 90% toabout 100%, from about 95% to about 100%, from about 96% to about 100%,from about 97% to about 100%, from about 98% to about 100% of light, inthe visible light spectrum, across its thickness. In some instances, thelayer 1005 may be formed of a polymer material, such as optical polymersused for ophthalmic lenses and/or transparent polymers. Some examplepolymers which may be used can include thiol-based polymers; MR seriespolymers commercially available from Mitsui Chemicals America, Inc. ofRye Brook, N.Y.; LPB or LPL series polymers commercially available fromMitsubishi Chemical Corporation of Tokyo, Japan; or OrmoStampcommercially available from micro resist technology GmbH of Berlin,Germany. In some instances, the layer 1005 may be formed of acombination of materials, such as a first layer of a first material anda second layer of a second material. Other examples are possible.

With continued reference to FIG. 10, the layer 1005 can have a firstmajor surface 1010 and a second major surface 1020. The first and secondmajor surfaces 1010, 1020 can be configured such that light containingimage information can propagate through the layer 1005 being guidedtherein. For example, the light can be guided through the layer 1005 byreflecting from the first 1010 and second 1020 major surfaces via totalinternal reflection from surfaces. In various implementations, the firstand second major surfaces 1010, 1020 can have relatively low surfaceroughness. For example, in some implementations, the surface roughnesscan be in a range from about 0.05 nm to about 3.0 nm (such as about 0.05nm, about 0.07 nm, about 0.1 nm, about 0.5 nm, about 1.0 nm, about 1.5nm, about 2.0 nm, about 2.5 nm, about 3.0 nm, etc.), in any rangeswithin this range (such as about 0.05 nm to about 2.5 nm, about 0.07 nmto about 2.5 nm, about 0.1 nm to about 2.5 nm, about 0.5 nm to about 2.5nm, about 0.7 nm to about 2.5 inn, about 1.0 nm to about 2.5 nm, about0.05 nm to about 2.0 nm, about 0.07 nm to about 2.0 nm, about 0.1 nm toabout 2.0 nm, about 0.5 nm to about 2.0 nm, about 0.7 nm to about 2.0nm, about 1.0 nm to about 2.0 nm, etc.), any values within these ranges,or in any ranges formed by such values. Without being bound by theory, awaveguide with a relatively low surface roughness can retain imagingquality. Accordingly, in various implementations, the first and secondmajor surfaces 1010, 1020 can have relatively low surface roughness suchthat layer 1005 can preserve image information and retain imaging.

In various implementations, the first major surface 1010 can include afirst smaller surface portion 1011 and a second larger surface portion1012 monolithically integrated with the layer 1005 and with each other1011, 1012. In some instances, the first smaller surface portion 1011can include at least a part of the in-coupling optical element 1030. Forexample, the first smaller surface portion 1011 can form at least a partof the in-coupling optical element 1030. In various implementations, thefirst smaller surface portion 1011 can be integrated with thein-coupling optical element 1030 such that the in-coupling opticalelement 1030 can be configured to efficiently couple light incident onthe in-coupling optical element 1030 into the layer 1005. As describedherein, the light can propagate through the layer 1005 by total internalreflection from the second major surface 1020 and the second largersurface portion 1012 of the first major surface 1010.

In some implementations, the in-coupling optical element 1030 can beconfigured to deflect light containing image information in the layer1005 of the waveguide 1000. In FIG. 10, the in-coupling optical element1030 comprises a tilted surface portion (e.g., the first smaller surfaceportion 1011). For example, the tilted surface portion can comprise thefirst smaller surface portion 1011 of the first major surface 1010tilted with respect to the second larger surface portion 1012 of thefirst major surface 1010 and the second major surface 1020. The tiltedsurface portion 1011 can be tilted in a range from about 30 degrees toabout 60 degrees with respect to a plane parallel the first 1010 and/orsecond 1020 major surfaces (such as about 30 degrees, about 35 degrees,about 40 degrees, about 45 degrees, about 50 degrees, about 55 degrees,about 60 degrees, etc.) in any ranges within this range (such as about30 degrees to about 50 degrees, about 35 degrees to about 50 degrees,about 40 degrees to about 50 degrees, about 30 degrees to about 55degrees, about 40 degrees to about 55 degrees, etc.), any values withinthese ranges, or in any ranges formed by such values. In someembodiments, the angle of tilt can be based at least in part on thethickness T of layer 1005 of the waveguide 1000.

In some implementations, the tilted surface portion 1011 can form a partof an indentation (or facet) 1050 in the layer 1005. With continuedreference to FIG. 10, the indentation 1050 can have a depth D (orheight) and width W. In some implementations, the depth D of theindentation 1050 can be less than the thickness T of the layer 1005. Insome instances, the depth D of the indentation 1050 can be at least halfthe thickness T or at least three quarters the thickness T of the layer1005. For example, the indentation 1050 can have a depth D of about 0.5T, about 0.6 T, about 0.75 T, about 0.8 T, about 0.9 T, etc. or can havea depth D in any ranges formed by such values. Other values and rangesare possible. In some implementations, the indentation 1050 can have adepth D substantially equal to the thickness T of the layer 1005.

In some instances, the depth D of the indentation 1050 can be in a rangefrom about 50 microns to about 550 microns (such as about 50 microns,about 75 microns, about 100 microns, about 150 microns, about 200microns, about 250 microns, about 300 microns, about 350 microns, about400 microns, about 450 microns, about 500 microns, about 550 microns,etc.), in any ranges within this range (such as about 50 microns toabout 500 microns, about 75 microns to about 500 microns, about 100microns to about 500 microns, about 75 microns to about 550 microns,about 100 microns to about 550 microns, about 150 microns to about 550microns, etc.), any values within these ranges, or in any ranges formedby such values. In some instances, the depth D of the indentation 1050can be outside these ranges.

In some instances, the width W of the indentation 1050 can be in a rangefrom about 25 microns to about 350 microns (such as about 30 microns,about 40 microns, about 50 microns, about 75 microns, about 100 microns,about 150 microns, about 200 microns, about 250 microns, about 300microns, about 350 microns, etc.), in any ranges within this range (suchas about 25 microns to about 300 microns, about 50 microns to about 300microns, about 75 microns to about 300 microns, about 30 microns toabout 350 microns, about 40 microns to about 350 microns, about 50microns to about 350 microns, about 75 microns to about 350 microns,etc.), any values within these ranges, or in any ranges formed by suchvalues. In some instances, the width W of the indentation 1050 can beoutside these ranges.

In some implementations, the indentation 1050 can comprise air.Alternatively, the indentation 1050 can comprise the same material aslayer 1005 or another substantially optically transparent material(e.g., a material with substantially similar refractive index). In somesuch implementations, the indentation 1050 can form at least part of aprism (e.g., a triangular prism) having a depth D and width W asdescribed herein with the tilted surface portion 1011 forming one of thesurfaces of the prism. Accordingly, some implementations of waveguidescan include an integrated in-coupling optical element 1030 in the formof a prism. In various implementations, the prism can be configured toreflect the light containing the image information in the layer 1005 ofthe waveguide 1000. For example, in some implementations, the prism canbe configured to reflect light by total internal reflection as lightstrikes a surface of the prism at an angle greater than the criticalangle.

Conventional gratings used as an in-coupling element can potentiallyresult in non-uniform brightness of an image due to differingdiffraction efficiencies with respect to input angle. Advantageously, invarious implementations, an in-coupling optical element 1030 comprisinga prism can achieve higher uniform reflectivity with respect to inputangle (extremely uniform reflectivity in some instances), and thus canimprove the brightness uniformity of the display's output image. Inaddition, in certain implementations described herein, an in-couplingoptical element 1030 comprising an integrated prism of the same materialas the waveguide (or a material with substantially similar refractiveindex) can achieve near-perfect index-matching with the waveguide (orsubstantially similar index-matching) without an interface (e.g., arough surface) between the prism and the waveguide material. In somesuch implementations, the in-coupling optical element 1030 can reduceback reflection into the projector (achieve extremely low backreflection in some instances), and thus reduce ghost image artifacts (noghosting in some instances). Furthermore, the in-coupling opticalelement 1030 comprising a prism integrated with a surface 1011 of thewaveguide 1000 can allow direct contact with the waveguide 1000, leadingto increased in-coupling between a light projector and waveguide 1000,and can simplify the manufacturing process by simplifying and/oreliminating the alignment step between the prism and waveguide duringassembly.

FIG. 11 illustrates another example waveguide with an integratedin-coupling optical element. The example waveguide 1100 is similar tothe example waveguide 1000 in FIG. 10 (e.g., first major surface 1110,second major surface 1120, layer 1105, indentation 1150, one or morelight distributing elements 1135, one or more out-coupling opticalelements 1140, etc.), except the tilted surface portion 1111 can form atleast part of a turning mirror. For example, in some implementations,the in-coupling optical element 1130 can include a layer 1145 ofreflective material (e.g., metallization) disposed on the tilted surfaceportion 1111. In some instances, the reflective layer 1145 can include ametal film (e.g., Au, Al, Ag, or any reflective metal). The thickness ofthe metal film can be in a range from about 5 nm to about 500 nm (suchas about 5 nm, about 10 nm, about 20 nm, about 30 nm, about 40 nm, about50 nm, about 75 nm, about 100 nm, about 150 nm, about 200 nm, about 250nm, about 300 nm, about 350 nm, about 400 nm, about 450 nm, about 500nm, etc.), in any ranges within this range (such as about 5 nm to about400 nm, about 5 nm to about 450 nm, about 10 nm to about 400 nm, about10 nm to about 450 nm, about 5 nm to about 500 nm, about 10 nm to about500 nm, about 50 nm to about 500 nm, about 100 nm to about 500 nm,etc.), any values within these ranges, or in any ranges formed by suchvalues. In some implementations, the indentation 1150 may be filled withreflective material or filler. The in-coupling optical element 1130comprising a turning mirror (e.g., a metallized tilted surface portion)can be configured to reflect the light containing image information inthe layer 1105 of the waveguide 1100. An in-coupling optical element1130 comprising a turning mirror integrated with a surface of thewaveguide 1100 can allow direct contact with the waveguide 1100, leadingto increased in-coupling between a light projector and waveguide, andcan simplify the manufacturing process by simplifying and/or eliminatingthe alignment step between the turning mirror and waveguide duringassembly.

In some implementations, the tilted surface portion 1111 may extendcompletely through the thickness of the waveguide layer 1105 such thatthe tilted surface portion 1111 is an edge (e.g., a surface extendingbetween the major surfaces) of the waveguide layer 1105 instead of aportion of the first major surface 1110. In other words, in someimplementations, the in-coupling optical element 1130 can be integratedwith an edge of the waveguide layer 1105 instead of a major surface1110.

FIG. 12 illustrates another example waveguide with an integratedin-coupling optical element. The example waveguide 1200 is similar tothe example waveguide 1100 in FIG. 11 (e.g., first major surface 1210,second major surface 1220, layer 1205, indentation 1250, one or morelight distributing elements 1235, one or more out-coupling opticalelements 1240, etc.), except the tilted surface portion 1211 of thein-coupling optical element 1230 has curvature. For example, in thein-coupling optical element 1230 illustrated in FIG. 12, the firstsmaller surface portion 1211 of the first major surface 1210 is curvedwith respect to the second larger surface portion 1212 of the firstmajor surface 1210 and the second major surface 1220. As anotherexample, the curved surface portion 1211 may be an edge portion of thewaveguide 1205.

In various implementations, the in-coupling optical element 1230comprising a turning mirror (e.g., a metallized curved surface portion)can be configured to reflect the light containing image information inthe layer 1205 of the waveguide 1200. In some implementations, thecurved surface portion 1211 can be configured to provide optical power(e.g., a powered turning mirror). In some implementations, the curvedsurface portion 1211 can supplement the optical power of othercomponents (e.g., supplement the optical power of the exit pupilexpanders) and/or make the optical power of other componentsunnecessary. In some examples, the curved surface portion 1211 can beconfigured to provide positive optical power. In some suchimplementations, the tilted surface portion 1211 can have concavecurvature from the perspective of most locations within thesubstantially optically transparent layer 1205. As another example, thecurved surface portion 1211 can be configured to provide negativeoptical power. In some such implementations, the tilted surface portion1211 can have a convex curvature from the perspective of most locationswithin the layer 1205.

FIG. 13 illustrates another example waveguide with an integratedin-coupling optical element. In the example waveguide 1300, the curvedsurface portion 1311 can form at least part of a lens 1351 (e.g., aspherical, cylindrical, parabolic, freeform lens, etc.) of an integratedprism 1352 and lens 1351. In the in-coupling optical element 1330illustrated in FIG. 13, the first smaller surface portion 1311 of thefirst major surface 1310 is curved with respect to the second largersurface portion 1312 of the first major surface 1310 and the secondmajor surface 1320. In some implementations, the curved surface portion1311 can be convex as seen from most of the waveguide 1305. In someexamples, the curved surface portion 1311 can form a positive poweredlens. In some implementations, the curved surface portion 1311 can beconcave as seen from most of the waveguide 1305. In some examples, thecurved surface portion 1311 can form a negative powered lens. In variousimplementations, the integrated prism 1352 and lens 1351 can beconfigured to direct the light containing the image information in thelayer 1305 of the waveguide 1300. For example, in some implementations,the prism 1352 can be configured to reflect light by total internalreflection as light strikes a surface of the prism 1352 at an anglegreater than the critical angle, and the lens 1351 can be configured tofocus and/or refract light into the layer 1305. Forming at least part ofa lens 1351 with a surface 1311 of the waveguide 1300 can improve thecoupling of light between a light projector and waveguide, and cansimplify assembly by eliminating the alignment step between the lens andwaveguide.

FIG. 14 illustrates another example waveguide with at least part of alens 1460 integrated with the waveguide 1400. In the example illustratedin FIG. 14, the entire lens 1460 is monolithically integrated with thewaveguide 1400. Although the lens 1460 is illustrated as integrated witha major surface 1420 of the waveguide layer 1405, in someimplementations, the lens 1460 can be integrated with an edge of thewaveguide layer. In addition to improving coupling of light andsimplifying assembly, monolithically integrating a lens with thewaveguide can reduce the total footprint (e.g., size and/or weight) of awaveguide display device by eliminating a lens component in theprojector and/or a lens component between the projector and waveguide.In some implementations, the lens 1460 can comprise of a spherical,cylindrical, parabolic, or freeform lens. Any shapes are possible. Insome instances, the lens 1460 can be a convex lens. In some examples,the lens 1460 can provide positive optical power. In someimplementations, the lens 1460 can be a concave lens. In some examples,the lens 1460 can provide negative optical power.

In some implementations, the lens 1460 can be aligned with anotherin-coupling optical element. For example, as illustrated in FIG. 15, thein-coupling optical element 1530 can be configured to turn light intolayer 1505 after passing through the lens 1560. In some instances, thein-coupling optical element 1530 can be disposed on a surface 1510 ofthe layer 1505 opposite the surface 1520 on which the lens 1560 isdisposed. In some other instances, the in-coupling optical element 1530can be disposed on a surface adjacent the surface on which the lens isdisposed. In some other instances, the in-coupling optical element 1530can be disposed on the same surface on which the lens is disposed. Insome implementations, the in-coupling optical element 1530 can beintegrated with a surface of the waveguide 1500. For example, thein-coupling optical element 1530 can include any of the in-couplingoptical elements described herein (e.g., an integrated facet, prism,turning mirror, lens, or a combination thereof).

As another example, the in-coupling optical element 1530 can include anintegrated grating. For instance, in some implementations, a firstsmaller surface portion 1511 of the first major surface 1510 can form atleast part of a grating (e.g., the first smaller surface portion 1511can include undulating surface relief). The grating can be a reflectivegrating. In some instances, the linewidth of the grating can be in arange from about 25 nm to about 550 nm (such as about 25 nm, about 50nm, about 60 nm, about 70 nm, about 75 nm, about 100 nm, about 150 nm,about 200 nm, about 250 nm, about 300 nm, about 350 nm, about 400 nm,about 450 nm, about 500 nm, about 550 nm, etc.), in any ranges withinthis range (such as about 25 nm to about 400 nm, about 50 nm to about400 nm, about 25 nm to about 450 nm, about 50 nm to about 450 nm, about25 nm to about 500 nm, about 50 nm to about 500 nm, about 75 nm to about500 nm, about 100 nm to about 500 nm, about 50 nm to about 550 nm, about75 nm to about 550 nm, etc.), any values within these ranges, or in anyranges formed by such values. Other examples are possible.

In some instances, the pitch of the grating can be in a range from about150 microns to about 650 microns (such as about 150 microns, about 200microns, about 250 microns, about 300 microns, about 350 microns, about400 microns, about 450 microns, about 500 microns, about 550 microns,about 600 microns, about 650 microns, etc.), in any ranges within thisrange (such as about 150 microns to about 500 microns, about 150 micronsto about 550 microns, about 150 microns to about 600 microns, about 200microns to about 500 microns, about 200 microns to about 550 microns,about 200 microns to about 600 microns, etc.), any values within theseranges, or in any ranges formed by such values. Other examples arepossible.

Other examples of in-coupling optical elements can be integrated with asurface of the waveguide. In addition, although various implementationsare described herein as in-coupling optical elements, other opticalelements can also be integrated with a surface of the waveguide. Forexample, light distributing elements 1035, 1135, 1235, 1335, 1435, 1535and/or out-coupling optical elements 1040, 1140, 1240, 1340, 1440, 1540can be integrated with a surface of the waveguide. Further, althoughvarious implementations of light distributing elements 1035, 1135, 1235,1335, 1435, 1535 and/or out-coupling optical elements 1040, 1140, 1240,1340, 1440, 1540 are illustrated as gratings, the light distributingelements and/or the out-coupling optical elements can be any of theintegrated optical elements described herein.

Some implementations can include one or more anti-reflective structuresto reduce reflections when the viewer is viewing through the waveguide.For example, as shown in FIG. 16 anti-reflective structures 1665 areprovided adjacent the in-coupling optical element 1630. One or moreanti-reflective structures 1665 can also be provided adjacent and/oropposing an out-coupling optical element 1640 (or a light distributingelement). One or more anti-reflective structures 1665 can be provided onany surface portion of the waveguide 1600. In FIG. 16, the in-couplingoptical element 1630 and the out-coupling optical element 1640 areillustrated as gratings integrated with a surface 1620 of the waveguide1600 (e.g., similar to grating 1530 shown in FIG. 15). In variousimplementations, the optical elements (e.g., in-coupling opticalelement, the out-coupling optical element, and/or the light distributingelement) can be any of the integrated optical elements described herein.

With conventional anti-reflective coatings, multiple layers of coatingsare usually provided, and it may be challenging to surround a gratingwith such layers. Further, there are generally costs associated withproviding each additional layer of conventional anti-reflective coating.In various implementations, at least a part of an anti-reflectivestructure can also be integrated with a surface of the waveguide (andcan surround a grating in some implementations). For example, a surfaceportion 1621 of the waveguide 1600 can form at least part of theanti-reflective structure 1665. In some implementations, theanti-reflective structure 1665 can include a surface relief pattern. Forinstance, the anti-reflective structure 1665 can comprise an undulatingpattern. In some implementations, the undulating pattern can undulate inone dimension or one direction. In some implementations, the undulatingpattern can undulate in two dimensions or two directions. The undulatingpattern can include a periodic pattern. For example, the period of thepattern can be in a range from about 25 nm to about 250 nm (such asabout 25 nm, about 50 nm, about 75 nm, about 100 nm, about 125 nm, about150 nm, about 175 nm, about 200 nm, about 250 nm, etc.), in any rangeswithin this range (such as about 25 nm to about 200 nm, about 50 nm toabout 200 nm, about 75 nm to about 200 nm, about 100 nm to about 200 nm,about 50 nm to about 250 nm, about 75 nm to about 250 nm, about 100 nmto about 250 nm, etc.), any values within these ranges, or in any rangesformed by such values. In some implementations, the pitch of theanti-reflective structure 1665 can be such that the anti-reflectivestructure 1665 is not diffractive to visible light. Other examples arepossible.

In some instances, the height of the pattern can be in a range fromabout 5 nm to about 250 nm (such as about 5 nm, about 10 nm, about 20nm, about 30 nm, about 50 nm, about 75 nm, about 100 nm, about 125 nm,about 150 nm, about 175 nm, about 200 nm, about 250 nm, etc.), in anyranges within this range (such as about 5 nm to about 200 nm, about 10nm to about 200 nm, about 50 nm to about 200 nm, about 10 nm to about250 nm, about 50 nm to about 250 nm, about 75 nm to about 250 nm, about100 nm to about 250 nm, etc.), any values within these ranges, or in anyranges formed by such values. Other examples are possible.

FIG. 16A shows a magnified image of an example anti-reflective structureadjacent an in-coupling grating. FIG. 16B shows a magnified image of theexample anti-reflective structure. As shown in these figures,nanostructures can be integrated with a surface of the waveguide. Invarious implementations, the extremely small sizes can have an effectiveindex with air such that the structure can act similar to ananti-reflective coating. An anti-reflective structure that is integratedinto a surface portion of the waveguide can advantageously beselectively provided on desired portions of the waveguide. For example,one or more anti-reflective structures can be provided to surround anin-coupling grating.

In some implementations, the anti-reflective structure can includematerial disposed on the surface relief pattern. For instance, in someexamples, the material can have a desired index of refraction. In someimplementations, the anti-reflective structure can reduce (and/orminimize in some instances) the reflection of the image generated by anadjacent waveguide. In some implementations, the anti-reflectivestructure can reduce (and/or minimize in some instances) the phaseretardation as light impinges on a surface.

An anti-reflective structure can be optically aligned with an opticalelement. In some instances, an anti-reflective structure can beoptically aligned with an optical element associated with anotherwaveguide. For example, the anti-reflective structure 1665 can beconfigured to facilitate passage of light through the waveguide 1600 toanother waveguide. With reference to FIG. 9A, various implementationsmay include a stack 660 of waveguides 670, 680, 690. As illustrated inFIG. 9A, the in-coupling optical elements 700, 710, 720 can be laterallyoffset from one another such that each in-coupling optical element 700,710, 720 can receive light without that light passing through anotherin-coupling optical element 700, 710, 720. Additionally, ananti-reflective structure can be optically aligned with an in-couplingoptical element associated with another waveguide. For example, ananti-reflective structure (e.g., 1665 shown in FIG. 16) can bepositioned on waveguide 670 above an in-coupling optical element (e.g.,710 in FIG. 9A) for waveguide 680 such that light 780 can transmitthrough the anti-reflective structure and waveguide 670 and be incidenton the in-coupling optical element 710 for coupling into waveguide 680.As another example, an anti-reflective structure can be configured toreduce (and/or minimize in some instances) reflection from lightout-coupled from a waveguide and directed to the user. In someimplementations, an anti-reflective structure can be optically alignedwith an out-coupling optical element and/or light distributing element.Referring to FIG. 9A, since light out-coupled by waveguide 680 passesthrough waveguide 670, an anti-reflective structure can be positioned onthe side of waveguide 670 nearest to waveguide 680. Other examples arepossible.

As described herein, various implementations can include an integratedoptical element. For example, some implementations can include a surfaceportion that forms at least a part of the optical element (e.g.,in-coupling optical element, light distributing element, out-couplingoptical element, anti-reflective structures, etc.). In someimplementations, at least part of the optical element can be formed whenforming the surfaces of the waveguide. As an example, someimplementations can be molded such that at least a part of the opticalelement can be formed into a surface of the waveguide. For instance,with reference to FIG. 16, some implementations can include a waveguidecomprising a molded layer 1605 of substantially optically transparentmaterial. Surface portions 1621, 1622 can be monolithically integratedwith the molded layer 1605 and with each other 1621, 1622. One 1621 ofthe surface portions can include at least a part of a molded opticalelement 1630. In some examples, the layer 1605, the surfaces 1610, 1620,and the surface relief pattern 1665 can form a molded optic. Thewaveguides 1000, 1100, 1200, 1300, 1400, 1500 in FIGS. 10 to 15 can alsobe molded. In some examples, the layer (e.g., 1005, 1105, 1205, 1305,1405, 1505), the first surfaces (e.g., 1010, 1110, 1210, 1310, 1410,1510), the second surfaces (e.g., 1020, 1120, 1220, 1320, 1420, 1520),and at least a part of the optical element (e.g., tilted surface portion1011, 1111, curved surface portion 1211, 1311, lens 1460, 1560, grating1530) can form a single molded optic.

Any of the waveguides 1000, 1100, 1200, 1300, 1400, 1500, 1600, orcombinations thereof, may be utilized as one of the waveguides of thewaveguide stacks 260 (FIG. 6) or 660 (FIGS. 9A-9C), e.g., as one of thewaveguides 270, 280, 290, 300 or 310 (FIG. 6) or 670, 680, or 690 (FIGS.9A-9C). In addition, any of the optical elements described herein can beprovided on any of the waveguides. For example, any of the opticalelements 1030, 1130, 1230, 1330, 1460, 1530, 1560, 1630 may correspondto any of the in-coupling optical elements 700, 710, or 720 (FIGS.9A-9C), the light distributing elements 730, 740, or 750 and/orout-coupling optical elements 570, 580, 590, 600, or 610 (FIG. 6) or800, 810, or 820 (FIGS. 9A-9C). As another example, any of the opticalelements 1030, 1130, 1230, 1330, 1460, 1530, 1560, 1630 may correspondto any of the features (e.g., lenses) 320, 330, 340, 350, 360, or 620(FIG. 6). In some implementations, one or more anti-reflectivestructures 1665 may be provided on any of the waveguides 270, 280, 290,300, or 310 (FIG. 6) or 670, 680, or 690 (FIGS. 9A-9C). Further,although some implementations have described the optical elements 1030,1130, 1230, 1330, 1460, 1530, 1560, 1630, 1665 as integrated with amajor surface of a waveguide, any of the optical elements 1030, 1130,1230, 1330, 1460, 1530, 1560, 1630, 1665 can be integrated with an edgeof a waveguide (e.g., a surface extending between the major surfaces).

Example Methods of Making Waveguides

As described herein, at least part of an optical element (e.g., at leastpart of an in-coupling optical element, a light distributing element, anout-coupling optical element, an anti-reflective structure, etc.) may beintegrated with the waveguide layer. As described herein, at least partof the waveguide surface can form at least a part of the opticalelement, which can simplify the manufacturing of the waveguide anddevices/systems incorporating the waveguides (e.g., fewer steps and/orfewer, if any, alignment issues). By forming at least a part of theoptical element with a surface portion of the waveguide, at least a partof the optical element can be perfectly index-matched with the waveguidelayer and without an interface therebetween. Further, in someimplementations, by forming at least a part of the optical element witha surface portion of the waveguide, optical elements can be formed onselective portions of the waveguide.

In various implementations, the waveguide layer (e.g., 1005, 1205, 1305,1405, 1505, 1605) may be formed using a flowable material. At least partof an optical element may be integrated with the waveguide layer byimprinting and subsequently hardening or curing of the imprintedmaterial. As an example method, the waveguide can be formed by moldingas described herein. Other types of molding can be used such asinjection molding. Inkjet, lithography, and/or nano-imprinting can alsobe used in some implementations, e.g., to include optical elements suchas lenses and/or prisms. In various implementations, the method can beused to form a variety of shapes and sizes (e.g., macro-level,micro-level, and/or nano-level sized features) and to form well-alignedfeatures. Some implementations can also achieve relatively flat surfaces(e.g., low surface roughness) without additional post processing steps(e.g., without polishing). Further, some implementations can beperformed repetitively and relatively inexpensively (e.g., inexpensivematerials, equipment, and operation).

FIGS. 17A-17D illustrate an example method of forming a waveguide withan integrated optical element. With reference to FIG. 17A, a pair ofmolds 2001, 2002 configured to face one another is provided. At leastone of the molds 2001, 2002 can comprise an imprint 2011, 2012 of atleast a part of an optical element. The imprint 2011, 2012 may be thenegative of the desired portion of the optical element to be defined inthe waveguide layer to be formed. For simplicity, the molds 2001, 2002are illustrated as having a pattern of raised features, e.g., to formone or more integrated gratings and/or anti-reflective structures asdescribed herein. In some other implementations, the imprint may be thenegative of at least a part of a prism, lens, integrated prism and lens,and/or a turning mirror (tilted and/or curved) as described herein. Itwill be appreciated that the imprints can be provided on the molds 2001,2002 to form any optical element, any combination of optical elements,and/or any additional structures as desired. With continued reference toFIG. 17A, a mass of material 2003 for forming the waveguide layer can bedeposited on mold 2001 (e.g., between molds 2001, 2002). As describedherein, the material 2003 can be a flowable material. For example, thematerial 2003 can be a polymer (e.g., a resin).

With reference to FIG. 17B, the molds 2001, 2002 can be brought togetherto compress the material 2003, thereby forming the waveguide layer. Forexample, the molds 2001, 2001 can contact the material 2003 such that atleast one of the molds 2001, 2002 transfers the corresponding imprintinto the material 2003.

With reference to FIG. 17C, the compressed material 2003 may besubjected to a hardening process. As an example, the compressed material2003 may be subjected to a curing process (e.g., exposure to ultravioletlight) to harden the material to form a substantially solid waveguidelayer 2005. As illustrated, the negative imprint 2011, 2012 can defineat least a part of the optical element in the waveguide layer 2005.

With reference to FIG. 17D, the molds 2001, 2002 can be moved apartrelative to one another and the waveguide layer 2005 can be releasedfrom the molds 2001, 2002, thereby forming the waveguide 2000 such thata surface portion of the waveguide forms at least a part the opticalelement. In some implementations, additional steps can be performed tofabricate the remaining part of the optical element, e.g., depositingmaterial on the formed part of the optical element. For example, atilted surface portion (e.g., 1130 of FIG. 11) or a curved surfaceportion (e.g., 1230 of FIG. 12) may be metallized. As another example, amaterial can be deposited on a surface relief pattern (e.g., 1665 ofFIG. 16).

In the foregoing specification, the invention has been described withreference to specific embodiments thereof. It will, however, be evidentthat various modifications and changes may be made thereto withoutdeparting from the broader spirit and scope of the invention. Thespecification and drawings are, accordingly, to be regarded in anillustrative rather than restrictive sense.

Indeed, it will be appreciated that the systems and methods of thedisclosure each have several innovative aspects, no single one of whichis solely responsible or required for the desirable attributes disclosedherein. The various features and processes described above may be usedindependently of one another, or may be combined in various ways. Allpossible combinations and subcombinations are intended to fall withinthe scope of this disclosure.

Certain features that are described in this specification in the contextof separate embodiments also may be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment also may be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination may in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination. No single feature orgroup of features is necessary or indispensable to each and everyembodiment.

It will be appreciated that conditional language used herein, such as,among others, “can,” “could,” “might,” “may,” “e.g.,” and the like,unless specifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/or stepsare included or are to be performed in any particular embodiment. Theterms “comprising,” “including,” “having,” and the like are synonymousand are used inclusively, in an open-ended fashion, and do not excludeadditional elements, features, acts, operations, and so forth. Also, theterm “or” is used in its inclusive sense (and not in its exclusivesense) that when used, for example, to connect a list of elements, theterm “or” means one, some, or all of the elements in the list. Inaddition, the articles “a,” “an,” and “the” as used in this applicationand the appended claims are to be construed to mean “one or more” or “atleast one” unless specified otherwise. Similarly, while operations maybe depicted in the drawings in a particular order, it is to berecognized that such operations need not be performed in the particularorder shown or in sequential order, or that all illustrated operationsbe performed, to achieve desirable results. Further, the drawings mayschematically depict one more example processes in the form of aflowchart. However, other operations that are not depicted may beincorporated in the example methods and processes that are schematicallyillustrated. For example, one or more additional operations may beperformed before, after, simultaneously, or between any of theillustrated operations. Additionally, the operations may be rearrangedor reordered in other embodiments. In certain circumstances,multitasking and parallel processing may be advantageous. Moreover, theseparation of various system components in the embodiments describedabove should not be understood as requiring such separation in allembodiments, and it should be understood that the described programcomponents and systems may generally be integrated together in a singlesoftware product or packaged into multiple software products.Additionally, other embodiments are within the scope of the followingclaims. In some cases, the actions recited in the claims may beperformed in a different order and still achieve desirable results.

Accordingly, the claims are not intended to be limited to theembodiments shown herein, but are to be accorded the widest scopeconsistent with this disclosure, the principles and the novel featuresdisclosed herein.

What is claimed is:
 1. A waveguide comprising: a polymer layercomprising substantially optically transparent material having first andsecond major surfaces configured such that light containing imageinformation can propagate through said polymer layer being guidedtherein by reflecting from said first and second major surfaces viatotal internal reflection, wherein said first surface includes firstsmaller and second larger surface portions monolithically integratedwith said polymer layer and with each other, said first smaller surfaceportion comprising at least a part of an in-coupling optical elementconfigured to couple light incident on said in-coupling optical elementinto said polymer layer for propagation therethrough by reflection fromsaid second major surface and said second larger surface portion of saidfirst major surface, wherein said first smaller surface portioncomprises a tilted surface portion forming an indentation in saidpolymer layer, wherein said indentation has a depth that is less thanthe thickness of the polymer layer and that is at least ½ the thicknessof the polymer layer, wherein said polymer layer including said at leasta part of said in-coupling optical element comprises a molded optic suchthat the first and second surfaces have a surface roughness betweenabout 0.1 nm to about 2.0 nm.
 2. The waveguide of claim 1, wherein saidin-coupling optical element comprises a turning mirror configured todeflect light containing image information in the waveguide.
 3. Thewaveguide of claim 2, wherein said turning mirror comprises said firstsmaller surface portion of said first major surface tilted with respectto said second larger surface portion of said first major surface andsaid second major surface.
 4. The waveguide of claim 2, wherein saidturning mirror has optical power.
 5. The waveguide of claim 4, whereinsaid powered turning mirror comprises said first smaller surface portionof said first major surface curved with respect to said second largersurface portion of said first major surface and said second majorsurface.
 6. The waveguide of claim 2, wherein said turning mirrorfurther comprises metallization disposed on said first smaller surfaceportion of said first major surface.
 7. The waveguide of claim 1,wherein said in-coupling optical element comprises a lens.
 8. Thewaveguide of claim 7, wherein said lens comprises said first smallersurface portion of said first major surface curved with respect to saidsecond larger surface portion of said first major surface and saidsecond major surface.
 9. The waveguide of claim 1, further comprising agrating.
 10. The waveguide of claim 9, wherein said grating has anundulating surface relief.
 11. An optical system comprising: one or morewaveguides comprising the waveguide of claim
 1. 12. The optical systemof claim 11, wherein said one or more waveguides comprise at least twoof the waveguides.
 13. The optical system of claim 11, wherein theoptical system is a head mounted display system configured to projectlight to an eye of a user to display augmented reality image content ina vision field of said user.
 14. The optical system of claim 13, furthercomprising a frame configured to be supported on a head of the user; animage projector configured to project an image; and an eyepiece disposedon the frame, said eyepiece configured to direct light into said user'seye to display augmented reality image content to the user's visionfield, at least a portion of said eyepiece being transparent anddisposed at a location in front of the user's eye when the user wearssaid head-mounted display system such that said transparent portiontransmits light from the environment in front of the user to the user'seye to provide a view of the environment in front of the user, saideyepiece comprising said one or more waveguides.
 15. The optical systemof claim 14, wherein the image projector comprises a scanning fiberdisplay.